Traditional nail enamel can contain a large amount of nitrocellulose, primarily because nitrocellulose provides good adhesion of the compositions to nails upon application. Such conventional nail polish compositions (with or without nitrocellulose) require solvent-based removal products to remove them from nails. However, it is desirable to avoid such solvent-based removers, both, from a personal perspective (to avoid damage to nails) and an environmental perspective (to avoid damage to the environment).
Other types of nail polish compositions exist. For example, UV (ultraviolet) gel compositions are known. UV gel compositions typically consist but are not limited to a layer of basecoat for adhesion to the nails, two color coats to enhance the color and one topcoat for shine and durability. Each layer of each coat needs to be cured (polymerized) with a UV or LED Lamp. Such polymerizable compositions have been described for example in U.S. Pat. No. 7,375,144 and WO2014/086875 the entire contents of which are hereby incorporated by reference.
The adhesion of UV gel nail compositions to the nail surface and cohesive force between the layers of multiple UV gel treatment is so strong that it is difficult to remove such compositions from nails. To remove such UV gel products from nails, it is usually required to soak nails with a harsh solvent such as acetone for at least 10 minutes or more to effect removal. Frequent and/or prolonged use of such solvents in this manner can damage nails such as, for example, by making them dry and brittle. At the same time, the removal process is time-consuming.
In the past, proposed solutions to improve the removal of UV gel nail compositions have focused on altering the composition of the UV gel layers themselves, for example by including additives which are soluble in solvents like acetone, ethyl acetate, butyl acetate, etc. to the layers. For instance, US2011082228A, US2011081306A, US2011060065A, US2011182838A, US2011182838A and US2011274633A relate to the use of a non-reactive, solvent-dissolvable polymer such as cellulose acetate butyrate, cellulose acetate propionate, and mixtures to enhance removal properties. Adding such non-reactive, solvent-dissolvable compounds improves saturation of the coatings by solvent and hence can speed up the removal process. The speed of removal depends on the type and the quantity of additives introduced in the composition. However, the use of solvent to remove the composition is still required.
Another proposed solution to improve removal of UV gel nail compositions is described in WO2014/088570 and WO2014/028021. These publications disclose the use of a water-based basecoat composition (primer) prior to the application of UV gel color coat(s) and/or UV gel topcoat, thereby allowing easy removal of all coats with the use of water. However, such nail applications have poor wear.
There remains a need for UV gel compositions that are safe, adhere well to nails and can be easily and quickly removed with minimum damage to nails.
The inventive nail treatment system provides the unique combination of basecoat containing a non-UV curable adhesive latex with a second coat (which preferably is a color coat) containing both photocrosslinkable urethane (meth)acrylates oligomers and (meth)acrylate monomers. The inventive nail treatment system optionally may also include a third or “topcoat” which optionally may also include photocrosslinkable urethane (meth)acrylates oligomers and (meth)acrylate monomers. The compositions of the invention deliver very strong adhesion to the nail and good wear, while at the same time the treatment system can be easily removed with the use of warm, soapy water.
Without being bound by theory, it is believed that (meth)acrylate monomers which are characterized as good adhesion promoters having excellent solvency power, improve adhesion between the basecoat and the second coat (which preferably is the color coat). Due to their capability of being powerful solvents, they partially solubilize and at the same time penetrate the basecoat of the inventive system which increases adhesion. Simultaneously, the photocrosslinkable urethane (meth)acrylates present in the inventive color/topcoat improve removability of said nail treatment system due to formation of a very strong and cohesive film which can be peeled off from the nail surface as a whole piece.
Furthermore, the presence of non-UV curable adhesive latex in the basecoat composition additionally enhances the removability of the inventive treatment system from the nails. Because the non-UV curable latex is hydrophilic, its exposure to warm and soapy water results in swelling. This results in decreased of adhesion between nails and the second and top coats of the inventive nail treatment system. The reduced adhesion force allows for easy peeling of the inventive nail treatment from the nail surface. Starting from the free edge of the nail, the consumer can easily remove the treatment system of inventive compositions.
As per this invention, the removal method of the nail treatment system does not require the use of harsh for nails, organic solvent, just warm and soapy water.